/* Four primary destinations share the existing site header. */
@media (max-width: 640px) {
  .site-header.history-navigation {
    display: grid;
    grid-template-columns: minmax(0, 1fr) auto;
    gap: 0 16px;
    padding-top: 10px;
    padding-bottom: 8px;
  }

  .history-navigation .site-brand { justify-self: start; }
  .history-navigation .site-theme-toggle { grid-column: 2; grid-row: 1; }
  .history-navigation .site-nav {
    grid-column: 1 / -1;
    grid-row: 2;
    gap: 24px;
    max-width: 100%;
    overflow-x: auto;
    scrollbar-width: thin;
  }
  .history-navigation .site-nav a { font-size: 13px; }
}